Pro plan. Claude works through a connection and HTTP steps, which are part of Pro and Agency (and the free trial). Anything you already have keeps working on every plan. See Plans and billing.
How it connects: Anthropic’s API with your key in the
x-api-key header and an anthropic-version header. See Anthropic’s Messages API docs. The model id is yours to choose from Anthropic’s docs.Before you start
- Anthropic billing: the API is billed per token on your Anthropic account, separately from Claude.ai plans.
- An API key: create one in the Anthropic Console.
1. Connect Anthropic
In Kerux, open Integrations > Connections, click Connect on Custom API (under Developers):- How it signs in: API key in a header, Header name
x-api-key, paste the key. - Base URL:
https://api.anthropic.com
2. Rate the fit
After Invitation accepted, add a Webhook / HTTP step namedclaude:
{{steps.claude.response.body.content.0.text}}. Add a Condition on it: strong notifies the owner, weak gets a lighter sequence. Add tags records the fit on the contact.
Kerux already sorts replies by itself (reply types), so you don’t need Claude for that.
Test with one contact
In the Builder, click Test to open Test on one contact. The journey shows the request and Claude’s answer.Common errors
401 authentication_error
401 authentication_error
The key is wrong or the header name isn’t
x-api-key.400 invalid_request_error
400 invalid_request_error
A required field is missing (
model, max_tokens, messages) or the model id is wrong. The message says which.429 or 529
429 or 529
Rate limit or overload on Anthropic’s side. Kerux retries later on its own.